Flare stack gas burner

ABSTRACT

A flare stack gas burner for waste combustible gases at both low and high pressure from oil refineries and the like is disclosed with separate delivery systems for the combustion gases, which includes a stack with a top mounted burner tip, the stack carrying a centrally disposed high pressure gas supply pipe closed at the top and with a plurality of outwardly extending vanes with gas delivery slots, the tops of the vanes being angularly disposed in a plane with respect to radial lines through the center of the stack for a swirling action of the burning gas. A low pressure gas supply pipe is mounted to and extends upwardly along the outside of the stack to a ring manifold mounted to the burner tip with a plurality of inwardly extending vanes, with gas delivery slots, the vanes being interposed between the outwardly extending vanes and angularly disposed in the same direction. Air at variable controlled low pressure is delivered into the stack at the bottom and moves upwardly between the vanes for smokeless burning. Optional fluidic seals can be provided in both the low and high pressure gas supply lines to prevent flashback. Ignitors and pilots are provided exteriorly of said stack.

United States Patent [1 1 Straitz, III

11] 3,824,073 1 July 16, 1974 FLARE STACK GAS BURNER [75] lnventor: John F. Straitz, Ill, Jenkintown, Pa.

[73] Assignee: Combustion Unlimited Incorporated,

Elkins Park, Pa.

[22] Filed: Aug. 13, 1973 [21] Appl. No.: 387,785

Primary ExaminerCarroll B. Dority, J r. Attorney, Agent, or Firm-Zachary T. Wobensmith, 2nd; Zachary T. Wobensmith, Ill

57 ABSTRACT A flare stack gas burner for waste combustible gases at both low and high pressure from oil refineries and the like is disclosed with separate delivery systems for the combustion gases, which includes a stack with a top mounted burner tip, the stack carrying a centrally disposed high pressure gas supply pipe closed at the top and with a plurality of outwardly extending vanes with gas delivery slots, the tops of the vanes being angularly disposed in a plane with respect to radial lines through the center of the stack for a swirling action of the burning gas. A low pressure gas supply pipe is mounted to and extends upwardly along the outside of the stack to a ring manifold mounted to'the burner tip with a plurality of inwardly extending vanes, with gas delivery slots, the vanes being interposedbetween the outwardly extending vanes and angularly disposed in the same direction. Air at. variable controlled low pressure is deliveredinto the stack at the bottom and moves upwardly between the vanes for smokeless burning. Optional fluidic seals can be provided in both the low and high pressure gas supply lines to prevent flashback. Ignitors and pilots are provided exteriorly of said stack.

7 Claims, 4 Drawing Figures PATENTED JUL 1 81974 SHEET 1 BF 2 PATENYED Jill I 81974 SHEEIZBfZ 1 FLARE STACK GAS BURNER,

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to flare stack gas burners for both low and high pressure combustible waste gas from refineries and like, for smokeless burning without steam, with the gas delivered for burning from different interengaged burners.

2. Description of the Prior Art In industrial operations and particularly in the operation of oil refineries it becomes necessary from time to time to burn various surplus quantities of combustible gaseous materials. The characteristics of these materials both as to composition and pressure vary considerably and there is no practical way now known of utilizing these gases.

The composition of the gases might vary from a light stream such as methane and ethane to a heavy stream of unsaturates such as ethylene and propylene. Ecologicalconsiderations require that the gases be destroyed without atmospheric pollution and the most satisfactory disposal method is burning of the gases. The gases must be burned without discharge of unburned carbon particles or smoke into the atmosphere both for the lowest pressure and the highest pressure of the waste gases at all the various gas compositions.

Flare stack burners have heretofore been proposed for high and low pressure gas but'some of these have had serious limitations, particularly because of the difficulty of designing a unitary structure that will operate smokelessly at both low andhigh pressure and with varying gas compositions.

In addition at some locations there is inadequate or no steam available for smoke suppressionor other considerations, such as climatic conditions, might preclude the use of steam to assist in smoke suppression. 1

' Among the burners heretofore proposed are those shown in the US. Patents to Verner et al., No. 2,761,496; Webster, et al. No. 2,891,607; Shellentrager, No. 2,506,972; Rodman, No. 2,537,091; Zink et al., No. 2,779,399; Campbell'et al., No. 2,802,521;

- pressure combustible waste gases by use of separate interengaged gas delivery systems with forced air combustion.

SUMMARY OF THE INVENTION In accordance with the invention a flare stack gas burner is provided for burning of combustible waste gas at low and high pressures from two separate gas delivery systems by structure which includes a high pressure delivery pipe within the stack closed at the top by a closure plate on a burner tip portion and communicating with outwardly extending attached vanes angularly disposed in a horizontal plane from radial lines through the center of the stack, the vanes having slots at their top margins for-swirling the high pressure flare gas. A low pressure gas supply pipe is provided exteriorly mounted on the stack and connected to a manifold on the burner tip portion with inwardly extending angularly disposed vanes, with slots at the top margins of the vanes for swirling low pressure gas delivery. A low pressure air blower is provided at the bottom of the stack for introduction of air as a combustion inducing media and which air flows out past the vanes, for smokeless combustion of the high and low pressure waste gases. Ignitors and pilots are also shown.

It is the principal object of the invention to provide a flare stack gas burner which is highly effective for smokeless combustion of combustible waste gases at low and high pressure by reason of enhanced air mixing and turbulence generation.

Itis a further oject of the invention to provide a flare stack gas burner of the-character aforesaid in which the low pressure combustible waste gas and air at the vanes burns smokelessly.

It is a further object of the invention to provide a I flare stack gas burner in which the high pressure com- BRIEF DESCRIPTION OFTHE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawing forming part hereof, in which;

FIG. 1 is a view partly in elevation and partly in vertical section of a flare stack in accordance with the invention; a 1

FIG. 2 is a horizontal sectional view taken approximately on the line 2-2 of FIG. 1;

a FIG. 3 is a vertical sectional view taken approximately on the line 3-3 of FIG. 2, and

FIG. 4 is an enlarged vertical sectional view taken on the line 44 of FIG. 2.

It should, of course, be understood that the description and drawings hereinare illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.

Like numerals refer to like parts throughout the several views.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now more particularly to the drawings, a

' vertical stack pipe 10 is shown, circular in horizontal cross section, with a burner tip 11 removably mounted at the top, and at the bottom of which is mounted an air inlet pipe 12 with an axial fan (no.t shown) and a damper (not shown) toprovide low pressure air into the interior of the stack pipe 10 for combustion of the waste gas. The pipe 10 and burner tip 11 are preferably fabricated of steel and coated toreduce rust.

The stack pipe 10 has, in spaced relation thereto, a centrally disposed interior high pressure gas supply pipe 13 with its lower terminus communicating with the supply of high pressure waste gas to be burned. The pipe 13 is closed at the top by an annular closure plate 15.

plurality of fixed vanes 16. The vanes 16 are shown as made of converging side wall plates 17 and 18, closed at the bottom by a bottom wall- 19v and at the outer end by an end wall 20 and with intermediate stiffeners 21 parallel to the end wall 20. The plates 17 and 18 are separated at the top to provide a gas delivery slot 22 and at their inner ends the vanes 16 have their interiors in communication with the pipe 13.

The vanes 16 and their gas delivery slots 22. are each at an angle, in a horizontal plane, to a radial line through the center of the pipe 13 to impart a swirling motion to the high pressure gas delivered through the slots 22. v 1

In larger flare stacks, in order to prevent downflow in the pipe 13 in the interior of the stack pipe 10, whether by external wind conditions or contraction by cooling of hot gas in the system, and also to reduce fluid oscillations, a fluidic seal such as is shown in my prior US. Pat. No. 3,730,673 may be employed mounted in the supply line to prevent flashback.

A low pressure gas supply pipe 25 is provided exteriorly mounted to'the stack-pipe and extending upwardly to a horizontal manifold 26 removably mounted to the top of the burner tip 11. i v

The manifold 26, which is shown as'being square in cross section has a plurality of fixed vanes 30 extending inwardly'therefrom. The vanes 30-are similar to the vanes 16 and are made of converging side wall plates Hand 32, closed at the bottom by a bottom wall 33, and at their inner end by an end wall 34. Intermediate stiffeners 35 may be provided fastened to the side walls 31 and 32 andparallel to the end wall 34. The plates 31 and 32 are separated at the top to provide a gas delivery slot 36 and at their inner ends the vanes 30 have their interiors in communication with the interior of the manifold 26. The vanes 30 and their gas delivery slots 36 are each at an angle in a horizontal plane to a radial line through the centerline of the pipe 13 to impart a swirling motion to the low pressure gas delivered through the slots 36 for combustion. A fluidic seal such as is shown in my prior US. Pat. No. 3,730,673 may be employed in the supplypipe 2S and spaced outwardly from the pipe 13 to prevent flashback.

' The disposition ofthe vanes 16 and 30 is such that they are staggered alternately one between the other aroundthe perimeter of the tip 11.

' A plurality of gas pilots 38 are provided with their heads 39 disposed outside the manifold 26. The pilots 38 can be of the venturi air inspirating type and connected to a' gas manifold ring (not shown) to which combustible gas is supplied through a pipe 40. The gas pilots 38 can be supported by brackets 41 secured to the pipe 10.

In order to ignite the gas pilots 38, an igniter pipe 42 is provided through which a gas flame is directed when by the positioning of the slots 36 and with a whirling movement. 'Air is delivered tothe inner margins of the above the burner tip 11 which results flames from the slots 36 through the pipe 10 into the burner tip 11, as desired, by the blower (not shown) which provides the quantity of air needed for smokeless operation, as called for by a flow sensor (not shown) which is connected into the low pressure gas supply pipe 25.

If waste gas at high pressure isto be burned it is sup- I plied through pipe 13 to vanes 16 and thence through the slots 22 for combustion.

The inclination of vanes 16 and the inclination of .the slots 22 produces a whirling action which permits complete smokeless combustion of the waste gas.

if desired, the air blower (not shown) may be used to provide additional combustion air for high pressure gas with a high amount of unsaturates.

- The gases at low pressure and at high pressure may be burned at the same timeor independently as desired and without any back pressure effect which would impede the flow of the low pressure gas.

It should be noted that the flame does not reach the vanes clue to the turbulence but occurs several feet tion and enhanced tip life. I

, It will thus be apparent that structure has been provided with which the objects of the invention are achieved.

I claim: r t

l. A flare stack gas burner for combustible waste gas having an outer stack with a burner tip portion at its upperv end comprising a combustible high pressure waste gas supply pipe extending upwardly within said stack,

a plurality of outwardly extending hollow vanes at the upper end of the burner tip portion of said supply pipe with spaces therebetween and having ,upwardly facing gas delivery openings connected to said gas supply pipe for discharge of said high pressure waste gas for combustion,

a combustible low pressure waste gas supply pipe extending upwardly with respect to said stack,

a hollow manifold mounted to said burner tip portion to which said low pressure gas supply pipe is connected,

a plurality of inwardly extending hollow vanes contiguous to said first mentioned hollow vanes attached to said manifold with spaces therebetween and having upwardly facing gas delivery openings communicating with said manifold for discharge of 'said low pressure waste gas for combustion,

means associated with said stack pipe for supplying air therethrough for delivery of air through the spaces between said vanes for combustion of waste gas delivered through said supply pipes,

said vanes being disposed to impart a swirling action to the gas delivered therefrom and to the air delivered therebetween.

2. A flare stack gas burner as defined in claim'l in which said low pressure vanes are tilted.

3. A flare stack gas burner as defined in claim 1 in which said high pressure vanes are tilted.

4. A flare stack gas burner as defined in claim 1 in which said high pressure vanes have their slots disposed at an angle to a radius through the vertical longitudinal axis of said high pressure supply pipe.

in cooler opera- 6 5. A flare stack gas burner as defined in claim 4 in said low pressure. vanes and said high pressure vanes which are alternately disposed around the radius of said said low pressure vanes have their slots disposed at an tip. l

angle to a radius through the vertical longitudinal 7. A flare stack gas burner as defined in claim 1 in axis of the high pressure supply pipe. 5 which 6. A flare stack gas burner as defined in claim 1 in said manifold is square shape in cross section. 

1. A flare stack gas burner for combustible waste gas having an outer stack with a burner tip portion at its upper end comprising a combustible high pressure waste gas supply pipe extending upwardly within said stack, a plurality of outwardly extending hollow vanes at the upper end of the burner tip portion of said supply pipe with spaces therebetween and having upwardly facing gas delivery openings connected to said gas supply pipe for discharge of said high pressure waste gas for combustion, a combustible low pressure waste gas supply pipe extending upwardly with respect to said stack, a hollow manifold mounted to said burner tip portion to which said low pressure gas supply pipe is connected, a plurality of inwardly extending hollow vanes contiguous to said first mentioned hollow vanes attached to said manifold with spaces therebetween and having upwardly facing gas delivery openings communicating with said manifold for discharge of said low pressure waste gas for combustion, means associated with said stack pipe for supplying air therethrough for delivery of air through the spaces between said vanes for combustion of waste gas delivered through said supply pipes, said vanes being disposed to impart a swirling action to the gas delivered therefrom and to the air delivered therebetween.
 2. A flare stack gas burner as defined in claim 1 in which said low pressure vanes are tilted.
 3. A flare stack gas burner as defined in claim 1 in which said high pressure vanes are tilted.
 4. A flare stack gas burner as defined in claim 1 in which said high pressure vanes have their slots disposed at an angle to a radius through the vertical longitudinal axis of said high pressure supply pipe.
 5. A flare stack gas burner as defined in claim 4 in which said low pressure vanes have their slots disposed at an angle to a radius through the vertical longitudinal axis of the high pressure supply pipe.
 6. A flare stack gas burner as defined in claim 1 in which said low pressure vanes and said high pressure vanes are alternately disposed around the radius of said tip.
 7. A flare stack gas burner as defined in claim 1 in which said manifold is square shape in cross section. 